In the case of withdrawable circuit breakers which are fitted to withdrawable insert systems, there is frequently a need to protect the contacts in the withdrawable insert system from being touched accidentally. So-called shutters are used as closure apparatuses for this purpose, as is known. These shutters essentially include plates with openings which can move with respect to one another. In the closed position, the openings in a plate are covered by another plate, so that the contacts of the withdrawable insert system are not accessible. In the open state, the openings in the plates are located one above the other, so that the contacts of the withdrawable insert system are accessible for the withdrawable circuit breaker.
The plates are composed of either an insulating material or of metal. Withdrawable insert systems such as these are known from the documents DE 101 20 749 C1, DE 101 20 750 C1 and EP 0 803 140 B1.
Furthermore, the document GB 236 498 discloses a safety device for electrical switches, in which two plates can be moved with respect to one another so as to create an open position and a closed position. A specific movement device is used for movement.
The document EP 0 577 111 A2 also describes a closure apparatus for withdrawable circuit breakers. The closure apparatus can be locked in its closed position via a lock.
Furthermore, the document DE 2 416 274 A1 discloses a protection apparatus for electrical switch panels, which has a supporting device for panels which can be moved into the depth of the switchgear assembly.
Finally, the document CH 530 100 discloses a closure apparatus with three plates. Furthermore, rods on the movement device project so far forwards that two plates are first of all pushed outwards during insertion of the withdrawable circuit breaker, before the entire closure apparatus is moved towards the contacts.
Furthermore, the applicant is internally aware of withdrawable insert systems in which, during insertion of a withdrawable circuit breaker, the plates first of all move in lateral directions in order to create openings which are somewhat larger than the contact blades which are fitted in the withdrawable insert frame. The complete shutter then moves, in a corresponding manner to the movement direction of the withdrawable circuit breaker, in the direction of the switchgear assembly and is pushed over the contact blades, which are now free and can be made contact with by the laminate blocks of the switches. This movement is controlled, for example, by way of an appropriate mechanism in the insertion drive, or by mechanisms on the withdrawable insert frame.